Enhanced finding of subscribers in communications system

ABSTRACT

In the present solution, a gateway node (GMLC-I, PDC) of a communications system (S) receives a find-subscribers-in-area request from an application node (LAP), and a prioritization act is performed according to predetermined prioritization criteria. The prioritization act is performed on the basis of passive location data received in the gateway node (PDC), and one or more user terminals are selected as polling priority user terminals (UE, UE 2 ). On the basis of said selection, a core network node (MSC/VLR) is requested to perform an act for generating updated passive location data. Thus, the gateway node (PDC) receives updated passive location data including information on detected polling priority user terminals (UE, UE 2 ). On the basis of the updated data, the gateway node (GMLC-I, PDC) is able to provide information on the detected user terminals (UE, UE 2 ) to the application node (LAP).

FIELD OF THE INVENTION

The present invention relates to location-based services (LBS), and moreparticularly to a method of finding subscribers in an area.

BACKGROUND OF THE INVENTION

Mobile (wireless) communications systems provide mobility for a user ofthe communications system. An example of such a mobile communicationssystem is a public land mobile network (PLMN), of which a cellular radiocommunications network is an example. The cellular radio communicationsnetwork allows a mobile station (MS) to move from one location toanother. The network is organized in cells which define how thelocations are managed. The cells of a cellular radio network provide themobile stations with access to the communications system. The cell canbe defined as a certain geographical area which is provided withwireless coverage by at least one base station (BS) via a wirelessinterface between the base station and the user terminal. The basestation forms a part of a radio access network (RAN). The radio accessnetwork is connected to a core network (CN), which provides call controland performs mobility and high-level security functions such as locationupdating and authentication. In such systems, the mobile network and/orthe user terminal such as a mobile station may be utilized for providinginformation on the geographical location of the user terminal and theuser thereof. A communications system comprising the necessary networkelements, entities, functionalities and interfaces required to providelocation information is said to support location services (LCS).

Patent application publication US 2007/0015522 A1 discloses the use ofpassive location data for providing location services to a locationservices client. US 2007/0015522 A1 discloses a find subscribers in area(FSIA) functionality implemented in an intelligent gateway mobilelocation centre (GMLC). FSIA refers to a concept in which alocation-based services (LBS) application (i.e. a client) may requestfrom GMLC a list of subscribers that are located in a certaingeographical area. According to US 2007/0015522 A1, GMLC utilizespassive location data in order to find subscribers in a certaingeographical area. The passive location data may include any availabledata that includes some information about the location of a subscriberterminal. A mobile switching centre/visitor location register MSC/VLRsends the passive location data to GMLC. This passive location dataconsists of updates in the VLR database. In GSM and WCDMA systems, thecellular network knows within the accuracy of the location area where acertain terminal is. This is needed for paging purposes. Thus thepassive location data includes a location area code (LAC) and a cellidentity (CI) of a user terminal. The passive location data is updatedwhen the user terminal is active (e.g. due to a call or an SMS), whenthere is a location area change (the user terminal moves from onelocation area to another), and/or when there is a periodic locationupdate.

A problem associated with the above arrangement is that a FSIAfunctionality based on the passive location data is best-effort. Itcannot be guaranteed that all subscribers in the defined area are found.This is because there may not be valid passive location data availablee.g. for user terminals that have been idle.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is thus to provide a method, system,gateway node, and a core network node for implementing the method so asto solve the above problem. The objects of the invention are achieved bya method and an arrangement which are characterized by what is stated inthe independent claims. Preferred embodiments of the invention aredisclosed in the dependent claims.

The invention is based on the idea of enhancing the find subscribers inarea (FSIA) functionality with selective active location informationpolling. Active location information polling means that the systeminitiates activities to obtain location information on the userterminals. Selective means that active polling is only applied tocertain user terminals. In the present solution, a prioritization act isperformed in a gateway node according to predetermined prioritizationcriteria. The prioritization act is performed on the basis of passivelocation data received in the gateway node. By means of theprioritization, one or more user terminals are selected as pollingpriority user terminals. On the basis of said selection, a core networknode is requested to perform an act for generating updated passivelocation data on the user terminals. Thus the gateway node receivesupdated passive location data including information on polling priorityuser terminals detected in a defined area. On the basis of the updatedpassive location data, the gateway node is able to provide informationon the detected user terminals to an application node.

An advantage of the method and arrangement of the present solution isthat it enables the provision of applications such as location-basedadvertising. The present solution may be implemented by utilizingexisting hardware. The present solution enables utilization of idleperiods and unused transmission capacity of the location system andprovision of an enhanced end-user experience.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail bymeans of preferred embodiments with reference to the attached drawings,in which

FIG. 1 illustrates a communications system according to an embodiment ofthe present solution;

FIG. 2 illustrates signalling according to an embodiment of the presentsolution;

FIG. 3 is a flow chart illustrating the functioning of a passive datacollector according to an embodiment of the present solution;

FIG. 4 is a flow chart illustrating the functioning of a mobileswitching centre/visitor location register according to an embodiment ofthe present solution;

FIG. 5 illustrates an activity behaviour analysis according to anembodiment of the present solution;

FIG. 6 illustrates a geographical behaviour analysis according to anembodiment of the present solution.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the present solution will be describedwith reference to a cellular or wireless communications system, such asa third generation (or beyond 3G) mobile communications system or WLAN(wireless local area network). However, the solution is not intended tobe restricted to these embodiments. The present solution is applicableto any user terminal, network node, corresponding component(s), and/orto any communications system or any combination of differentcommunications systems capable of providing location information on userterminals. The communications system may be a fixed communicationssystem or a wireless communications system or a communications systemutilizing both fixed networks and wireless networks. The protocols used,the specifications of communications systems and network nodes,especially in mobile and wireless communication, develop rapidly. Such adevelopment may require extra changes to an embodiment. Therefore, allwords and expressions should be interpreted broadly and are intended toillustrate, not to restrict, the embodiment. The relevant inventiveaspect is the functionality concerned, not the network element or theequipment where it is executed.

In traditional (e.g. 3GPP and OMA) location-based services a clientrequests from a location server (e.g. a 3GPP gateway mobile locationcentre or OMA SUPL location platform) information on the location of adefined subscriber. By means of a FSIA service, the client may requestidentities of those subscribers that are in a defined area.

The present solution proposes performing selective active locationinformation polling to enhance FSIA, wherein active polling means thatthe system initiates activities to obtain location information on userterminals and wherein selective means that active polling is onlyapplied to certain user terminals. The present solution does not applyactive polling to all user terminals since this may overload thelocation system. In addition to FSIA, the present solution may also beapplied to any other functionality that is dependent on passive locationdata.

FIG. 1 illustrates a communications system S according to an embodimentof the present solution. Referring to FIG. 1, the communications systemS comprises a wireless network, such as a public land mobile networkPLMN or a wireless local area network (WLAN) operated by a networkoperator. The public land mobile network PLMN comprises a mobileswitching centre/visitor location register MSC/VLR, to which a userterminal UE is able to connect via a suitable access network such as aradio access network (RAN, not shown in FIG. 1). The system furthercomprises a location application LAP (such as an advertising engine)capable of requesting information on the the user terminals UE in anarea by contacting a gateway mobile location centre node GMLC-I. Thelocation application LAP may be implemented as a client that is externalto an operator network N. The gateway mobile location centre node GMLC-Iincludes a passive data collector function PDC connected to an actualgateway mobile location centre function GMLC and to an FSIA middlewarefunction MW. In GMLC-I, the passive data collector function PDC acts asan interface to PLMN and the FSIA middleware function MW acts as aninterface to LAP. FIG. 1 is a simplified version of a cellular orwireless network structure showing only components necessary forillustrating the present solution, even though those skilled in the artnaturally know that a general communications system also comprises otherfunctions and structures, which do not have to be described in moredetail herein. Although each network node or function UE, MSC, VLR,GMLC-I, PDC, GMLC, MW, LAP, PLMN, N has been depicted as one entity,different modules and memory may be implemented in one or more physicalor logical entities.

According to the present solution, if the location system has capacityto spare, it initiates active location information polling for selecteduser terminals in order to improve the likelihood of having passive oractive location information available for functions such as FSIA. Activelocation polling may refer to 1) a normal location procedure accordingto e.g. the 3GPP location services standards or the open mobilealliance's (OMA) secure user plane location (SUPL) standard, or 2) otheractivities that generate passive location data, for example, sending ofa zero-length short message to a user terminal or some other form ofpaging. Of these, a less loading one may be selected. The selection of auser terminal may be based on 1) categorization of certain userterminals as priority terminals (e.g. subscribers having a certain kindof higher priority subscription), 2) categorization of certain locationareas as priority areas (e.g. areas where there are ongoinglocation-based advertising campaigns using a FSIA functionalityregularly), 3) the activity behaviour of terminals, and/or 4) thegeographical behaviour of terminals.

FIG. 2 illustrates signalling according to an embodiment of the presentsolution. Referring to FIG. 2, in a message 2-1, a location update of auser terminal UE (or some other initializing event generating passivelocation data, such as an SMS, an MMS, a call, a location area change)is carried out between MSC/VLR and UE. In response to the initializingevent, a VLR database is updated (not shown), and MSC/VLR sends passivelocation data 2-2 to a passive data collector function PDC included in agateway mobile location centre GMLC-I. VLR is updated and thus thepassive location data is sent when the user terminal UE is active (e.g.due to a call or an SMS), when there is a location area change (the userterminal UE moves from one location area to another), and/or when thereis a periodic location update. A location application LAP (such as anadvertising engine) sends a find-subscribers-in-area (FSIA) request 2-3to an FSIA middleware function included in GMLC-I. The FSIA request 2-3includes a definition of a geographical area of interest. In response toreceiving the FSIA request, FSIA middleware MW sends 2-4, to the passivedata collector PDC, a request for information concerning which userterminals are in the cells covering the defined area of interest.According to the present solution, PDC makes decisions on priorities foractive location polling. This means that PDC defines 2-5 a pollingpriority list including information on priority user terminals UE whosecurrent location is of interest to the location system. (The procedurefor defining of the polling priority list is further described below inmore detail in connection with FIG. 3). After the polling priority listhas been defined, PDC interacts 2-6 with the actual GMLC functionalityin order to get location information. According to the present solutionGMLC-I (e.g. PDC and/or GMLC) is arranged to check 2-5, 2-6 whether ornot the location system has spare capacity for active polling. Forexample, the following information may utilized by GMLC-I for decidingwhether or not there is spare capacity for performing active polling ofpassive location data: 1) CPU load, 2) the number of location requestsreceived in GMLC-I from application clients within certain time period,and/or 3) the number of pending location requests, FSIA requests orother service requests. If it does have spare capacity, GMLC is arrangedto request 2-7 MSC/VLR to perform a location update of the userterminals UE included in the priority polling list. GMLC may, forexample, request MSC/VLR to transmit a blank short message (or a blankMMS message (multimedia message) or some other signalling message thatrequires the paging of the user terminal UE) to the user terminals UEincluded in the priority polling list in order to get updated locationinformation on the user terminals UE. In response to receiving therequest 2-7, MSC/VLR transmits the blank short message 2-8 to the userterminal UE, thus initiating a location update procedure 2-9 of the userterminal UE between UE and MSC/VLR. In a way, GMLC-I requests MSC/VLR tocarry out a forced paging and/or a forced location update of the userterminal UE. Thus MSC/VLR receives updated passive location data on theuser terminal UE. In a message 2-10, the updated passive location datais transmitted from MSC/VLR to PDC, wherein the updated passive locationdata is stored, at least temporarily, in PDC (not shown in FIG. 2).Based on the updated passive location data, PDC transmits a locationdata response 2-11 via MW to LAP. Thus LAP receives an FSIA response2-12 from GMLC-I, i.e. a list of the detected user terminals UE in thearea defined in the FSIA request.

It should be noted that the active location polling according to thepresent solution may be carried out continuously, e.g. as a backgroundprocess. Steps/messages 2-1 and 2-2 of FIG. 2 are normal passivelocation data processes going on in the system “all the time”.Accordingly, PDC may perform/initialize steps/messages 2-5 to 2-10 inthe system whenever there is spare time/capacity. Thus, the activelocation polling process (i.e. steps/messages 2-5 to 2-10) may becarried out before, during, and/or after the message 2-4 is received.PDC (or some other suitable network element) is able to perform theactive location polling whenever desired such that if a request (e.g. anFSIA request 2-3, 2-4) for passive location data is received, there is ahigher probability that valid passive location data is available.

FIG. 3 is a flow chart illustrating the functioning of a passive datacollector function PDC according to an embodiment of the presentsolution. Referring to FIG. 3, passive location data is received in thepassive data collector function PDC in step 3-1 from a mobile switchingcentre MSC/visitor location centre VLR. The passive location dataincludes information on one or more user terminals UE that are supposedto be in the PLMN area. In step 3-2, PDC receives a location datarequest from MW, including information on a find-subscribers-in-area(FSIA) request transmitted by a location application LAP. Based on thepassive location data, a polling priority list is formed in step 3-3 byincluding, in the polling priority list, information on the userterminals UE that are supposed to be in the PLMN area. In step 3-4, itis checked whether or not priority user terminals UE are defined in thelocation system. If priority user terminals UE are defined, non-priorityuser terminals are removed 3-5 from the polling priority list (or theyare put 3-5 to the bottom of the polling priority list). In step 3-6, itis checked whether or not priority location areas (LAs) are defined inthe location system. If priority location areas are defined, userterminals that are included in the polling priority list but that arenot located in these priority areas are dropped 3-7 from the pollingpriority list (or they are moved 3-7 to the bottom of the pollingpriority list). In step 3-8, an activity analysis may be carried out (asdescribed below in connection with FIG. 5) by the location system anduser terminals prioritized based on the activity analysis. In step 3-9,a geographical analysis may be carried out (as described below inconnection with FIG. 6) by the location system and user terminalsprioritized based on the geographical analysis. In step 3-10, it ischecked whether or not the system has spare capacity to carry out activelocation polling according to the present solution. If the system hasspare capacity, a procedure for receiving updated location information(e.g. sending a forced SMS and/or paging) on the user terminals includedin the polling priority list is initiated 3-11 by PDC. This means thatan active location data request is transmitted 3-11 from PDC to MSC/VLRvia GMLC. In step 3-12, PDC receives updated passive location data fromMSC/VLR, including information on the user terminals UE detected basedon the active location polling. The received updated passive locationdata is stored 3-12, at least temporarily, in PDC. Based on the updatedpassive location data, PDC is able to transmit 3-13 a location dataresponse via MW to LAP. The location data response includes a list ofthe detected user terminals in the area defined in the FSIA request. Instep 3-14, it is checked whether or not it is time to update the pollingpriority list (e.g. whether or not a predetermined time limit forupdating has been exceeded). If it is time to update the pollingpriority list, the process returns to step 3-4, from where it continuesby forming a(n updated) polling priority list by including all userterminals in the polling priority list etc. If it is not yet time toupdate the polling priority list, the process returns to step 3-10, fromwhere it continues by checking whether or not the location system hasspare capacity etc. Another option is that the process ends after step3-14 (not shown in FIG. 3). It should be noted that steps 3-3 to 3-12may be performed before, during, and/or after the step 3-2.

FIG. 4 is a flow chart illustrating the functioning of a mobileswitching centre/visitor location centre MSC/VLR according to anembodiment of the present solution. Referring to FIG. 4, a locationupdate or some other location-related procedure is carried out betweenMSC/VLR and at least one user terminal UE in step 4-1. In step 4-2,based on the location update of step 4-1, MSC/VLR transmits passivelocation data on the at least one user terminal UE to a passive datacollector PDC located in a gateway mobile location centre GMLC-I. I. Instep 4-3, MSC/VLR receives a send-SMS request (or some otherlocation-related request) from a gateway mobile location centre functionGMLC located in a gateway mobile location centre GMLC-I. The send-SMSrequest includes information about at least one user terminal UEincluded in a polling priority list. On the basis of the send-SMSrequest, MSC/VLR transmits 4-4 a blank short message (or some othersignalling message that requires paging of the user terminal UE) to theuser terminals UE included in the respective polling priority list.Based on the blank short messages, a “forced” location update of theuser terminals UE is carried out between MSC/VLR and UE, and thusMSC/VLR finds out updated passive location data on the user terminals UEof interest. In step 4-6, MSC/VLR transmits the updated passive locationdata to PDC.

Selection of user terminals for the active location polling may be basedon the behaviour of the user terminals, e.g. on the activity behaviourof the user terminals and/or on the geographical behaviour of the userterminals.

FIG. 5 illustrates an activity behaviour analysis according to anembodiment of the present solution. According to the embodiment, theprioritization logic is based on the activity behaviour of userterminals UE1, UE2, wherein the activity behaviour analysis is based onthe idea that it is advantageous to actively poll locations of thoseuser terminals that are less likely to generate updated passive locationdata (their passive location data may be obsolete). In the example ofFIG. 5, a first user terminal UE1 regularly generates passive locationdata (e.g. transmits/receives short messages SMS, makes/receives callsetc.). A second user terminal UE2 generates passive location data due toperiodic location updates only. Thus, it is more advantageous toprioritize the second user terminal UE2 for active location polling (itis better to poll the location of UE2, since it is less likely to havepassive location data). The activity behaviour analysis may beimplemented in the passive data collector PDC functionality since it isable to store history information (e.g. latest 5 passive location dataincidents/user terminal) on the user terminals.

FIG. 6 illustrates a geographical behaviour analysis according to anembodiment of the present solution. According to the embodiment, theprioritization logic is based on the geographical behaviour of userterminals UE1, UE2, wherein the geographical behaviour analysis is basedon the idea that it is advantageous to actively poll locations of thoseterminals that are more likely to move. If there is information on areasof interest (e.g. FSIA areas), speed and direction (detected from thepassive location data history stored in PDC) of the user terminal UE1,UE2 may also be utilized for the prioritization. In the example of FIG.6, the passive location data history shows that a first user terminalUE1 enters X a first cell C1 in a location area LA. Then the first userterminal UE1 is involved in two incidents X generating passive locationdata (e.g. SMS and a call) in a second cell C2. The passive locationdata history also shows that a second user terminal UE2 enters Y thefirst cell C1 in the location area LA. Then, the second user terminalUE2 is involved in an incident Y generating passive location data (e.g.an SMS) in a third cell C3 and in an incident Y generating passivelocation data (e.g. a call) in a fourth cell C4. If it is assumed thatUE1 and UE2 entered the location area LA essentially at the same timeand that the passive location data generating events happenedapproximately simultaneously, the second user terminal UE2 should beprioritized for active location polling on the basis of the fact thatUE2 moves more if compared to UE1. Further, if the FSIA area has beendefined as the find subscribers in area in the location area LA, adirection analysis shows that the second user terminal UE2 seems to bemoving towards it (towards a fifth cell C5). So, also on the basis ofthe direction analysis, UE2 should be prioritized for active locationpolling (as UE2 is more likely to enter the FSIA area than UE1). Thegeographical behaviour analysis may be implemented in the passive datacollector PDC functionality since it is able to store historyinformation on the user terminals.

The present solution enables enhancing the FSIA functionality in variouscustomer cases. For example, the present solution enables a timelydetection of user terminals in mobile advertising campaign areas (evenwhen using passive location data). For example, a mobile advertisingcampaign may be going on in a shopping centre, wherein the area of theshopping centre may be defined as an FSIA area (such as the FSIA area inFIG. 6). The location system according to the present solution is ableto provide information on the selected user terminals to a locationapplication so that the location application is able to initializetransmission of mobile advertisements to the selected user terminals.The mobile advertisements may include e.g. short messages, multimediamessages, e-mails, etc.

According to an embodiment, the location system is able to receive,collect, store, and/or evaluate information on the location behaviour ofthe user terminals in the FSIA area or close to it. For example, if itis assumed that a user terminal UE has just entered the FSIA area (e.g.a shopping centre) where a mobile advertising campaign is going on, theuser terminal UE may be defined as a priority user terminal as it hasnot yet received a specific mobile advertisement of the campaign. On theother hand, another user terminal that has already received theadvertisement may be defined as a non-priority user terminal. It shouldbe noted that some subscribers may not wish to receive mobileadvertisements. So, the location system may be arranged to define userterminals belonging to these subscribers as non-priority user terminals.The location system according to the present solution may further bearranged to define roaming user terminals as priority user terminalsonly for campaigns that are run in a defined language such as English.

It should be noted that the location system is able to provide to thelocation application LAP a list of user terminals in the areaanonymously so that the advertiser (e.g. the shopping centre) is able torun the advertising campaign without knowing the telephone numbers,mobile country codes, mobile network codes or any other identity data ofthe user terminals that are prioritized and/or receive the mobileadvertisements.

Instead of or in addition to MSC/VLR, some other operator networkelement such as a serving GPRS support node (SGSN), a home locationregister (HLR), a billing system, an external probe system, or areal-time traffic monitoring tool may be utilized in the presentsolution for the provision of passive location data.

Instead of sending a blank short message (SMS) to the selected userterminals, the present solution may involve sending a blank multimediamessage (MMS), for example.

The mobile advertisements may be sent to the selected user terminals inthe form of a short message (SMS), a multimedia message (MMS), email,etc.

According to an embodiment, the present solution involves transmitting asignalling message from the core network node MSC/VLR to a locatingfunction according to a secure user plane location SUPL standard inorder to locate a user terminal.

According to an embodiment, the present solution involves finding userterminals in a specific area for transmitting an alarm or a notificationto the user terminals. This embodiment may be applied e.g. in case ofemergency, like in case of fire.

An FSIA area according to the present solution may include a shoppingcentre, a school, an industrial plant or any other area wheretransmitting informative messages to user terminals in the area may beuseful.

The items and steps shown in the figures are simplified and only aim atdescribing the idea of the present solution. The steps/points,signalling messages and the related functions described above in FIGS. 1to 6 are in no absolute chronological order, and some of thesteps/points may be performed simultaneously or in an order differentfrom the given one. Other functions may also be executed between thesteps/points or within the steps/points and other signalling messagesmay be sent between the illustrated messages. Some of the steps/pointsor part of the steps/points can also be left out or integrated togetheror replaced by a corresponding step/point or part of the step/point. Theapparatus operations illustrate a procedure that may be implemented inone or more physical or logical entities. The signalling messages areonly exemplary and may even comprise several separate messages fortransmitting the same information. The messages serve as examples onlyand they may only contain some of the information mentioned above. Inaddition, the messages may also contain other information, and thetitles may deviate from those given above. Instead of or in addition toa home network node and/or a visited network node, the above-describedoperations may be performed in any other element of a communicationssystem.

In addition to prior art means, a system or system network nodes thatimplement the functionality of the present solution comprise means forproviding location information on user terminals in the area. Existingnetwork nodes and user terminals comprise processors and memory that maybe utilized in the operations of the present solution. Any changesnecessary in implementing the present solution may be carried out usingsupplements or updates of software routines and/or routines included inapplication-specific integrated circuits (ASIC) and/or programmablecircuits, such as EPLDs (electrically programmable logic device) orFPGAs (field programmable gate array).

It will be obvious to a person skilled in the art that, as technologyadvances, the inventive concept may be implemented in various ways. Theinvention and its embodiments are not limited to the examples describedabove but may vary within the scope of the claims.

1. A method of providing subscriber location information in acommunications system, the method comprising performing a prioritizationact according to predetermined prioritization criteria, wherein theprioritization act is performed on the basis of passive location datareceived in a gateway node from an operator network, the passivelocation data including location information on user terminals in theoperator network; selecting, on the basis of said prioritization act,one or more of said user terminals as polling priority user terminals;requesting, on the basis of said selecting, one or more network nodes inthe operator network to perform an act for generating updated passivelocation data; receiving the updated passive location data in thegateway node, the updated passive location data including information ondetected polling priority user terminals; and storing the receivedupdated passive location data in the gateway node.
 2. A method accordingto claim 1, wherein the prioritization act comprises evaluatingavailable transmission capacity of the system, wherein said requestingis carried out only if there is capacity available in the system forgenerating the updated passive location data.
 3. A method according toclaim 1, wherein the prioritization act comprises evaluating theactivity behaviour of the user terminal, wherein the user terminals, thepassive location data of which is obsolete, are prioritized.
 4. A methodaccording to claim 1, wherein the prioritization act comprisesevaluating the geographical behaviour of the user terminal, wherein theuser terminals that move the most are prioritized.
 5. A method accordingto claim 1, wherein it comprises transmitting a forced short message SMSor a multimedia message MMS to the polling priority user terminals.
 6. Amethod according to claim 1, wherein the passive location data includesdata generated based on a periodic location update of the user terminal.7. A method according to claim 1, wherein the passive location dataincludes data generated based on a location update of the user terminaldue to a call, a short message SMS, and/or a multimedia message MMS. 8.A method according to claim 1, the method comprising receiving, in thegateway node, a request for finding subscribers in an area from anapplication node; and on the basis of the updated passive location data,providing information on the user terminals detected in the area to theapplication node.
 9. A communications system wherein the system isconfigured to perform a prioritization act according to predeterminedprioritization criteria, wherein the prioritization act is performed onthe basis of passive location data received in a gateway node from anoperator network, the passive location data including locationinformation on user terminals in the operator network; select, on thebasis of said prioritization act, one or more of said user terminals aspolling priority user terminals; perform, on the basis of saidselecting, an act for generating updated passive location data; receivethe updated passive location data in the gateway node, the updatedpassive location data including information on detected polling priorityuser terminals; and store the received updated passive location data inthe gateway node.
 10. A communications system according to claim 9,wherein it is configured to receive, in the gateway node, a request forfinding subscribers in an area from an application node; and on thebasis of the updated passive location data, provide information on theuser terminals detected in the area to the application node.
 11. Agateway node of a communications system wherein the gateway node isconfigured to perform a prioritization act according to predeterminedprioritization criteria; wherein the gateway node is arranged to performthe prioritization act on the basis of passive location data receivedfrom an operator network, the passive location data including locationinformation on user terminals in the operator network; select, on thebasis of said prioritization act, one or more of said user terminals aspolling priority user terminals; request, on the basis of saidselecting, one or more network nodes in the operator network to performan act for generating updated passive location data; receive the updatedpassive location data, the updated passive location data includinginformation on detected polling priority user terminals; and store thereceived updated passive location data in the gateway node.
 12. Agateway node according to claim 11, wherein it is arranged to evaluatethe available transmission capacity of the system, wherein it isarranged to carry out said requesting only if there is capacityavailable in the system for generating the updated passive locationdata.
 13. A gateway node according to claim 11, wherein it is arrangedto evaluate the activity behaviour of the user terminals, wherein it isarranged to prioritize the user terminals, the passive location data ofwhich is obsolete.
 14. A gateway node according to claim 11 wherein itis arranged to evaluate the geographical behaviour of the userterminals, wherein it is arranged to prioritize the user terminals thatmove the most.
 15. A gateway node according to claim 11, wherein it isarranged to request the core network node to transmit a forced shortmessage SMS or a multimedia message MMS to the polling priority userterminals.
 16. A gateway node according to claim 11, wherein the passivelocation data includes data generated based on a periodic locationupdate of the user terminal, and/or data generated based on a locationupdate of the user terminal due to a location area change, a call, ashort message SMS, and/or a multimedia message MMS.
 17. A gateway nodeaccording to claim 11, wherein it is configured to receive a request forfinding subscribers in an area from an application node; and on thebasis of the updated passive location data, provide information on theuser terminals detected in the area to the application node.
 18. Agateway node according to claim 11, wherein it comprises a gatewaymobile location centre GMLC including a passive data collector PDCfunction.
 19. A core network node of a communications system, whereinthe core network node is capable of transmitting passive location datato a gateway node, wherein the core network node is configured toreceive, from the gateway node, a request to perform an act forgenerating updated passive location data on user terminals selected aspolling priority user terminals, transmit, on the basis of the request,to the polling priority user terminals or to a locating function, asignalling message for receiving location information on the pollingpriority user terminals, and transmit, in response to receiving thelocation information, the updated passive location data to the gatewaynode, the updated passive location data including information ondetected polling priority user terminals.
 20. A core network nodeaccording to claim 19, wherein the signalling message transmitted to theuser terminal includes a blank short message or a blank multimediamessage.
 21. A core network node according to claim 19, wherein thesignalling message transmitted to the locating function includes amessage according to a secure user plane location SUPL standard.
 22. Acore network node according to claim 19, wherein it is arranged totransmit a forced short message SMS or a multimedia message MMS to thepolling priority user terminals.
 23. A core network node according toclaim 19, wherein it includes at least one of a mobile switchingcentre/visitor location register MSC/VLR, a serving GPRS support nodeSGSN, a home location register HLR, a billing system, an external probesystem, and a real-time traffic monitoring tool.